Xerographic plate cleaning apparatus



P 5 'r. c. MURRAY ETAL 3,149,356

XEROGRAPHIC PLATE CLEANING APPARATUS Filed Nov. 1, 1962 5 Sheets-Sheet 1THOM C. MURRAY JOSE B. STONE B FRANKLIN s. REESE ATTORNEY Sept. 22, 1964Filed Nov. 1, 1962 T. C. MURRAY ETAL XEROGRAPHIC PLATE CLEANINGAPPARATUS 5 Sheets-Sheet 2 THOMAS C.

IN VENTOR.

MURRAY JOSEPH B. STONE FRANKLIN s. REESE ATTORNEY Sept. 22, 1964 v T. C.YMURRAY ETAL 3,149,356

XEROGRAPHIC PLATE CLEANING APPARATUS Filed Nov. 1, 1962 s Sheets-Sheet sFIG. 3

IN VEN TOR.

THOMAS C. MURRAY JOSEPH B. STONE BY FRANKLIN s, REESE %ww/M ATTORNEYSept. 22, 1964 T. c. MURRAY ETAL XEROGRAPHIC PLATE CLEANING APPARATUS 5Sheets-Sheet 4 Filed Nov. 1. 1962 INVENTOR. THOMAS C. MURRAY JOSEPH B.STONE FRANKLIN S. REESE ATTQRNEV l 1964 T. MURRAY ETAL 3,149,356

XEROGRAPHIC PLATE CLEANING APPARATUS Filed NOV. 1, 1962 5 Sheets-Sheet 5FIG. 6

INVENTOR. THOMAS amuanm BY JOSEPH B. STONE FRANKLIN S. REESE ATTORNEYUnited States Patent 3,149,356 XERDGRATHIC PLATE CLEANTNG APPARATUSThomas C. Murray, Rochester, Joseph B. Stone, Pentield, and Franklin S.Reese, Victor, N.Y., assignors to Xerox Corporation, Rochester, N.Y., acorporation of New York Filed Nov. 1, 1962, Ser. No. 234,696 2 Claims.((31. 15-1.5')

This invention relates to a xerographic plate cleaning apparatus andspecifically to apparatus adapted to automatically clean a xerographicplate with a web of fibrous material.

In the process of xerography, a metal plate containing a photoconductivesurface is charged, exposed and developed. That is, a uniformelectrostatic charge is placed on the plate surface. The plate is thenexposed to a light image of copy to be reproduced, resulting in a latentelectrostatic image of the original copy on the plate surface. Theelectrostatic image is developed by covering the plate surface with afinely divided powder. The powder adheres to the plate in the areascontaining electrostatic charge, thus producing a powder image of theoriginal copy. The powder image is transferred to a support materialsurface and is bonded thereto. A quantity of residual powder adheres tothe plate surface after the image is transferred to the support materialsurface and must be removed before the xerographic plate can be used todevelop a new image.

Heretofore cleaning of flat xerographic plates sometimes has been a handoperation wherein the plate conta ning the residual powder has beenmoved under an electrostatic discharge device and covered with anelectrostatic charge. The plate was then manually wiped with a softpowder absorbent material, such as cotton. The electrostatic chargeloosened the powder from the surface and the absorbent material wipedthe power off the surface. This method, though effective, was timeconsuming and dirty.

It is, therefore, the primary object of this invention to provideapparatus which will automatically clean a xerographic plate.

It is also an objective of this invention to provide a plate cleaningapparatus that will utilize a continuous web of material as the cleaningmedium.

A further object of this invention is to provide a xerographic platecleaning apparatus that will automatically clean a xerographic plate andplace the plate in a position where an operator may pick up the platefor reuse.

Further objects of this invention are to provide web cleaning apparatusfor use with flat xerographic plates, and to provide a web cleaningapparatus that does not require the attention of an operator, and isfaster and less expensive to operate than the existing methods.

These and other objects of the invention are attained by means of a webof fibrous material mounted on rollers and forced into moving contactwith a xerographic plate. A drive roll moves the plate through theapparatus and a cleaning roll forces the web into contact with the platesurface.

For a better understanding of the invention, as well as the objects andfurther features thereof, reference is had to the following detaileddescription of the invention to be read in connection with theaccompanying drawings, wherein:

FIG. 1 is an isometric view of one embodiment of a xerographic transferand cleaning unit;

FIG. 2 is a front view of the xerographic transfer and cleaning unitshown in FIG. 1 with portions broken away to show internal structure;

FIG. 3 is a sectional view of the xerographic transfer and cleaning unitshown in FIG. 1 taken along line 3--3 "ice of FIG. 1 with portionsbroken away to show internal structure;

FIG. 4 is an enlarged isometric view of one embodiment of a web cleaningassembly of the xerographic transfer and cleaning unit shown in FIG. 1;

FIG. 5 is a schematic representation of the web travel of the webcleaning assembly; and

FIG. 6 is a fragmentary sectional view taken along line 66 of FIG. 3.

Referring now to FIG. 1, there is shown a xerographic transfer andcleaning unit including a frame 1 enclosed by side covers 2, here shownbroken away to reveal the internal structure of the apparatus. The framel'has a front top cover 3, a rear top cover 4 and a pair of guide tracks5 extending along the top side edges. The top cover 3 is sized toreceive and support a xerographic plate 6. The plate 6 is properlypositioned on the top cover 3 by abutting two sides of the plate againsta front lip 7 and a side block 8 on the front and side top edges,respectively, of the frame 1.

The xerographic plate 6 consists of a photoconductive surface 9, such asselenium, on a conductive backing member 10. The photoconductive surface9 does not completely cover the plate member 10, thus leaving a borderor edge 11 around the outer periphery of the plate. When the plate 6 isplaced in the transfer unit, there is a powder image on thephotoconductive surface 9 which is to be transferred to a sheet of paperor support material. Proper alignment of the support material withrespect to the powder image is important for proper registration of thefinal transferred image onto the support material. To ensure that theplate 6 does not move during the transfer operation, a plate clamp 12 isprovided at the rear side of the plate 6 extending out of the rear topcover 4. Plate clamp 12 extends over front top cover 3, and plate 6 adistance sufficient to hold plate 6 but not to contact thephotoconductive surface 9. A pair of polyurethane pads 13 on each end ofthe clamp 12 press against the plate 6 holding it securely in position.

To place the plate clamp 12 into a locked position wherein plate 6 isheld rigidly in the transfer unit, as shown by the solid lines in FIG.6, a plate clamp lever 14, shown in FIG. 3, is moved "to the rear of thetransfer unit against the action of tension spring 15 mounted betweenthe rear top cover 4 and the clamp lever 14. The plate clamp leverpivots about a pin 16 mounted in a bracket 17 which is rigidly securedto a mounting block 18. The rearward movement of the plate clamp lever14 moves an arm 19 which extends upwardly from the plate clamp lever toengage a spring loaded yoke 30, pulling the yoke forward against tensionspring 31. The yoke 30 is a U-shaped member extending around achannel-shaped clamp mounting frame 32, rigidly secured to block 18.

The yoke 30 contains a pin or rod 33 (see FIG. 6) which extends throughtwo slots 34 in each of the clamp mounting frame sides. The pin 33extends across the channel-shaped mounting frame over a clamp receivingmember 35 which fits into the channel portion of the clamp mountingframe and is pivotally attached to the rear of the mounting frame 32 bypivot pin 36. The top side 37 of the clamp receiving member 35 isslanted or sloped from the clamp end downward to the pivoted end. Thepin 33 of the yoke 30 extends across the clamp receiving member andrides on the sloped surface 37. A pair of compression springs 38 in thebottom of the channel portion of the clamp mounting frame 32 pressupward on the bottom of the clamp receiving member 35 urging it to aposition shown by the dotted lines in FIG. 7. In this position, theplate clamp 12 would be away from the plate 6 in an unclamped positionand the yoke 30 would be toward the rear of the transfer unit, that is,drawn in around the mounting frame 32 with the pin a a CB 33extending'across the clamp receiving arm at the lowest point of thesloped surface 37.

As the movement of the clamp lever 14 pulls the yoke 30 forward, the pin33 rides on the sloped surface 37 of the clamp receiving member 35forcing the clamp receiving member downward into the channel of themounting frame 32 against springs 38. There is a grooved T slot in thebottom of the plate receiver member 35 which is adapted to receive arm39 of the plate clamp 12. The plate clamp 12 is held in the T slot by aleaf spring 40 and moves with the receiving member so that as thereceiving member is forced downward against the compression springs 38,the plate clamp moves downward and presses against plate 6.

The yoke 30 is held in a forward position holding the clamp 12 againstthe plate 6 by means of a locking arrangement consisting of an arm 41extending downward from the yoke 36 and engaging a yoke lock lever 42.The lock lever 42 is pivotally mounted on the mounting block 18 by apivot pin 43 and is urged into a locking position, as seen in FIG. 7, bya tension spring 44 attached to the frame 1 of the transfer unit. Theyoke lock has a notched end 45 which engages a projection 4-6 on the endof arm 41, and holds the yoke in a forward position. Clockwise movement,as seen in FIG. 6, of the yoke lock releases the arm .1 and permits theyoke to be drawn rearward by springs 31. Release action of the yoke lock42 is produced by a wire 47 attached to ejection lever arm 48 at thefront of the transfer unit, the action of which will be discussed morefully below.

To aid in the proper alignment of the support material and the powderirnage, a longitudinal paper guide 49 is mounted along the front topedge of the transfer unit and is attached to the frame 1 by means of ahinge member 50 beneath the level of the front top cover 3. When theplate 6 is placed in the transfer apparatus, the paper guide 49 is in anopen position, that is, swung away from and below the level of the fronttop cover 3. After the plate 6 is properly positioned on the front topcover 3 and is clamped in position with clamp 12, the guide 49 is swungupward onto plate 6 touching only the border portion 11. A small lateralpaper guide 51 is mounted on longitudinal paper guide 49 to adjust theimage registration on the support material in a lateral direction. Thepaper guide 51 is mounted in a slot 52 on paper guide 49 and isadjustably mounted therein by means of a set screw 53. When the paperguides 49 and 51 are in position, that is, a closed position overlyingthe top of the Xerographic plate 6, a sheet of support material isabutted against the paper guide 49 and against paper guide 51 andallowed to rest on the Xerographic plate 6.

The transfer of the Xerographic powder image from the plate surface tothe support material is effected by means of an electrostatic transferdevice 54. The transfer device 54, herein shown as a corotron, includesan array of one or more corona discharge electrodes 60, as seen in FIG.6, that are energized from a power supply PS-l through flexible powerline 61. The power line 61 passes through a protective insulated member63 and contains a loose loop 62 which permits movement of the corona 54across the entire length of the transfer unit. The discharge electrodes66 are enclosed by the shielding member 64 which is mounted in acorotron housing 65. The electrodes 69 and the housing 65 traverse thetransfer unit and are supported on each end by support member 66 mountedon roller brackets 67, each of which contain a pair of rollers 68adapted to ride on tracks 5. In operation, the electrostatic fieldcreated by the electrostatic transfer device is effective to tack thetransfer material electrostatically to the plate surface. Simultaneouslywith the tacking action, the electrostatic field attracts the tonerparticles comprising the Xerographic powder image from the plate surfacecausing them to adhere electrostatically to the surface of the transfermaterial. Manual movement of the corotron 54 along tracks causes thecorotron to traverse the support material and the xerographic plate.Simultaneous with the movement of the corona discharge device alongtrack 5, the operator depresses button 69 initiating operation of thepower supply PS1 to the corona electrodes 60. As the corotron approachesthe front of the transfer unit, the housing 65 contacts the leadingpoint 70 of the laterial paper guide 51 producing a tipping motion ofthe paper guide 51 which moves longitudinal paper guide 49 away from theplate 6. Paper guides 49 and 51 then fall downward to the front of thetransfer unit. The operator releases button 69 cutting off power to thecorona discharge electrodes and moves the corona discharge device backto the rear of the transfer unit. The paper or support materialcontaining a Xerographic powder image may now be removed from thexerographic plate 6.

After transfer of the powder image from the xerographic plate 6 to thesupport material, the support material is removed from the plate 6 andtransferred to a suitable fusing device, as for example, the typedisclosed in copending application, Ser. No. 227,472, filed October 1,1962, in the name of Thomas C. Murray et al.

The Xerographic plate may be removed from the transfer apparatus byactuating plate ejection lever 48. The ejection lever 48 extends througha pivot block 71 and terminates in a plate ejection arm 72. The ejectionarm 72 extends upward through an arcuate slot 73 in the top cover 3, toa point above the top cover 3. In the nonoperating position, theejection arm 72 is back toward the frame 1 out of contact with theXerographic plate. As the ejection lever 48 is actuated the wire 47releases the yoke locking device 42 which releases clamp 12 from theplate 6. Further movement of the ejection lever 30 moves the ejectionarm 72 along slot 73 contacting plate 6. Continued movement of arm 72forces plate 6 toward web cleaner 74.

As the plate 6 moves toward the web cleaner 74, it actuates microswitch75 initiating operation of motor MOT-1 and drive roll 111. The plate 6is forced between drive roll 111 and a cleaning roll 114 propelling theplate forward through the web cleaner 74. The ejection lever 48 isreleased and is returned to its non-operating position by means oftension spring 78 connected between the ejection arm 48 and a mountingrod 79 securely fastened to the frame 1.

After a Xerographic plate has been used to produce a powder image andthat image has been transferred to a support material, there is acertain quantity of residual powder which adheres to the plate surface.It is necessary to completely remove the residual powder prior toreusing the plate.

The residual powder is held on the plate by an electrostatic charge,therefore, prior to attempting to remove the powder from the platesurface, an opposite charge is applied to the plate surface. This isaccomplished by a stationary electrostatic discharge device 81 hereinalso shown as a corotron in FIG. 2 and of the same construction as thecorona charging device 54 except that it im- 7 parts a negative charge.As stated above, the Xerographic plate 6 trips microswitch 75 as it ispropelled forward by the ejection arm 48. Switch 75 is electricallyconnected to a power supply PS1 to supply the voltage potential tocorona 80. Therefore, during the time that the xerographic plate 6 ispassing over microswitch 75, it is being moved beneath the corotron andan electrostatic charge is being applied to the plate surface. Adisposable fibrous web of material 86 is then forced into slidingcontact with the plate surface and absorbs residual powder loosenedtherefrom by the application of electrostatic charge. The web cleaningapparatus, as seen in FIG. 4, consists of a pair of support framemembers 87 secured to main frame 1 in a position to receive plate 6 asit is urged forward by ejection arm 72. Mounted between the supportframes 87 are a pair of bearing plates 88 spaced from the frames 87 byspacers 89 and pivotally secured thereto by fasteners 90. Mountedbetween the bearing plates 38 are a web supply shaft 91, a web cleaningshaft 92 and a web take-up shaft 93 rotatably journaled in bearings 94,9S and 96, respectively. An adjustment bar 84 is secured to both framemembers 37 and contains a pair of set screws 85 that bear against thebearing plates 38. Movement of set screws 84 produces a pivotingmovement of the bearing plates 88 and an adjustment of the space betweena cleaning roll 114 on shaft 92 and a drive roll 111 thus regulating thepressure applied to the Xerographic plate.

Power to the web cleaner is transmitted from motor MOT-1 through drivebelt 97 to main pulley 98 to drive shaft 99. Drive shaft 99 isappropriately journaled in the support frame 87 and drives the platedrive roll 111. The opposite end of drive shaft 99 is journaled in theopposite support frame 87. A pinion 101 mounted on shaft 99 drives agear 182 to supply power to a power transmission shaft 1'93. Shaft 103is journaled in the support frames 87 and, at the opposite end from thegear 1622, contains a pinion 1134 which transmits power to a series ofgears 1115' and pinions 1% to produce a speed reduction in a gear 107mounted on the web cleaning shaft 92. The speed of the shaft 99 anddrive roll 111 is approximately 20 times as fast as the speed of the webcleaning shaft 92, thus producing a sliding motion of the plate past theweb, and continually exposing clean web to the plate surface.

The cleaning shaft 92 contains a resilient roller around which the web86 passes, and is pressed into intimate contact with the surface of theXerographic plate 6. On the opposite end of the web cleaning shaft 92 isa pulley 1133 and a belt 109 for transmitting power to a pulley 119mounted on a web take-up shaft 93. Shaft 93 accumulates used webmaterial after it has been on contact with the surface of theXerographic plate 6. Clean web material is supplied from a roll 113 onsupply roll shaft 91. The drive roll 111 consists of resilient materialmounted on shaft 99 and is kept free of lint and dirt by a brush 124supported by the frame members 87.

There is seen schematically in FIG. 5 a web 86 supplied from a roll 113on a shaft 91 which passes around a rubber or resilient cleaning roll114 on shaft 92 and contacts Xerographic plate 6, passes behind a webguide 115 and is wound up on a take-up roll 116 on shaft 93. To permitreplacement of the web supply roll 113 and removal of take-up roll 116,the bearings 95 and 94 are constructed with cut-out portions 117. A pairof lock clips 11% are joined to each of the bearing plates 88 to retainthe shafts 91 and 93 in the bearings 94 and 96 respectively. The lockclips 118 contain a vertical slot 19 and are held in bearing plates 88by studs 120 which pass through slots 119. The lock clips 118 aremovable in a vertical direction by lifting upward on a lever 121. Theupward movement of the lever 121 removes the locking arm 122 from thecut-out portions 117 of bearings 94 and 9d, freeing the shafts 91 and93.

As the plate 6 passes over microswitch 75, the microswitch is held in adepressed position but as the trailing edge of the plate passes over themicroswitch, the switch is released turning off the power to driverolls. The switch 75 is positioned and adjusted to cut off the drivemotor when the margin of the plate 6 is between rolls 111 and 114. Theplate is then stationary and supported essentially by the border 11,between the web cleaning I011 114 and the plate support roll 111. Theforward or leading edge of the plate is supported upon a bracket 123extending outward from the support frame 87. The plate will remain inthis position supported by the bracket 123 and the web cleaning roll 114and the plate support roll 111, until such time as it is picked up by anoperator.

While the present invention as to its objects and ad vantages, asdescribed herein, has been carried out in specific embodiments thereof,it is not desired to be limited thereby, but it is intended to cover theinvention broadly within the spirit and scope of the appended claims.

What is claimed is:

1. A web cleaning apparatus for use in cleaning xerographic platesincluding a pair of support frame members,

a pair of bearing plates pivotally connected to said frame members,

a drive roll journaled for rotation in said frame members to move axerographic plate between the frame members,

a cleaning roll journaled for rotation in the bearing plates andpositioned adjacent to the drive roll,

said cleaning roll adapted to force a web of cleaning material intocontact with the surface of a Xerographic plate as the plate passesbetween the cleaning roll and the drive roll,

adjusting means to pivot said bearing plates relative to said framemembers to change the spacing between the cleaning roll and the driveroll,

means to rotate said drive roll to produce movement of a xerographicplate,

and means to rotate said cleaning roll to present clean web material tothe plate surface during passage of the plate between the cleaning rolland the drive roll.

2. A web cleaning apparatus for use in cleaning Xero graphic platesincluding a pair of support frame members,

a pair of bearing plates pivotally connected to said frame members,

a drive roll journaled for rotation in said frame members to move aXerographic plate between the frame members,

a cleaning roll journaled for rotation in the bearing plates andpositioned adjacent to the drive roll,

said cleaning roll adapted to force a web of cleaning material intocontact with the surface of a xerographic plate as the plate passesbetween the cleaning roll and the drive roll,

a web supply roll and a web take-up roll to continuously supply new webmaterial to said cleaning roll and to take up used web material after ithas passed around said cleaning roll,

adjusting means to pivot said bearing plates relative to said framemembers to change the spacing between the cleaning roll and the supportroll,

means to rotate said drive roll to produce movement of a Xerographicplate,

and means to rotate said cleaning roll and said take-up roll to presentclean web material to the plate surface during passage of the platebetween the cleaning roll and the drive roll.

References Cited in the file of this patent UNITED STATES PATENTS

1. A WEB CLEANING APPARATUS FOR USE IN CLEANING XEROGRAPHIC PLATESINCLUDING A PAIR OF SUPPORT FRAME MEMBERS, A PAIR OF BEARING PLATESPIVOTALLY CONNECTED TO SAID FRAME MEMBERS, A DRIVE ROLL JOURNALED FORROTATION IN SAID FRAME MEMBERS TO MOVE A XEROGRAPHIC PLATE BETWEEN THEFRAME MEMBERS, A CLEANING ROLL JOURNALED FOR ROTATION IN THE BEARINGPLATES AND POSITIONED ADJACENT TO THE DRIVE ROLL, SAID CLEANING ROLLADAPTED TO FORCE A WEB OF CLEANING MATERIAL INTO CONTACT WITH THESURFACE OF A XEROGRAPHIC PLATE AS THE PLATE PASSES BETWEEN THE CLEANINGROLL AND THE DRIVE ROLL, ADJUSTING MEANS TO PIVOT SAID BEARING PLATESRELATIVE TO SAID FRAME MEMBERS TO CHANGE THE SPACING BETWEEN THECLEANING ROLL AND THE DRIVE ROLL, MEANS TO ROTATE SAID DRIVE ROLL TOPRODUCE MOVEMENT OF A XEROGRAPHIC PLATE, AND MEANS TO ROTATE SAIDCLEANING ROLL TO PRESENT CLEAN WEB MATERIAL TO THE PLATE SURFACE DURINGPASSAGE OF THE PLATE BETWEEN THE CLEANING ROLL AND THE DRIVE ROLL.